Biologic-free remission of established rheumatoid arthritis after discontinuation of abatacept: a prospective, multicentre, observational study in Japan

Objective. The aim of this study was to determine whether biologic-free remission of RA is possible with discontinuation of abatacept. Methods. Japanese RA patients in 28-joint DAS with CRP (DAS28-CRP) remission ( 2 years of abatacept treatment in a phase II study and its long-term extension entered this 52 week, multicentre, non-blinded, prospective, observational study. At enrolment, the patients were offered the option to continue abatacept or not. The primary endpoint was the proportion of patients who remained biologic-free at 52 weeks after discontinuation. Clinical, functional and structural outcomes were compared between those who continued and those who discontinued abatacept. Results. Of 51 patients enrolled, 34 discontinued and 17 continued abatacept treatment. After 52 weeks, 22 of the 34 patients (64.7%) remained biologic-free. Compared with the continuation group, the discontinuation group had a similar remission rate (41.2% vs 64.7%, P = 0.144) although they had a significantly higher mean DAS28-CRP score at week 52 (2.9 vs 2.0, P = 0.012). The two groups were also similar with regard to mean HAQ Disability Index (HAQ-DI) score (0.6 for both, P = 0.920), mean change in total Sharp score (TSS; 0.80 vs 0.32, P = 0.374) and proportion of patients in radiographic remission (TSS4 0.5) at the endpoint (64.3% vs 70.6%, P = 0.752). Those attaining DAS28-CRP < 2.3 or < 2.7 without abatacept at the endpoint had significantly lower HAQ-DI score and/ or CRP at enrolment. Non-serious adverse events occurred in three patients who continued or resumed